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I’ve been having a few issues with my certificate renewals with Certbot (the artist formerly known as Let’s Encrypt). If I did a dry-run for renewing my certificates…

/etc/certbot-auto renew --dry-run

… I kept getting this message:

Encountered vhost ambiguity but unable to ask for user guidance in non-interactive mode. Currently Certbot needs each vhost to be in its own conf file, and may need vhosts to be explicitly labelled with ServerName or ServerAlias directories. Falling back to default vhost *:443…

It turns out that Certbot doesn’t like HTTP and HTTPS configurations being lumped into one .conf file. Instead it expects to see all the port 80 stuff in a domain.com.conf file, and the port 443 stuff in a domain.com-ssl.conf file.

I installed the Let’s Encertbot client with this incantation (which, like everything else here, will need root-level access so if none of these work, retry using sudo in front of the commands):

wget https://dl.eff.org/certbot-auto
chmod a+x certbot-auto

Seems like a good idea to put that certbot-auto thingy into a directory like /etc:

mv certbot-auto /etc

Rather than have Certbot generate conf files for me, I’m just going to have it generate the certificates. Here’s how I’d generate a certificate for yourdomain.com:

/etc/certbot-auto --apache certonly -d yourdomain.com

The first time you do this, it’ll need to fetch a bunch of dependencies and it’ll ask you for an email address for future reference (should anything ever go screwy). For subsequent domains, the process will be much quicker.

The result of this will be a bunch of generated certificates that live here:

/etc/letsencrypt/live/yourdomain.com/cert.pem

/etc/letsencrypt/live/yourdomain.com/chain.pem

/etc/letsencrypt/live/yourdomain.com/privkey.pem

/etc/letsencrypt/live/yourdomain.com/fullchain.pem

Now you’ll need to configure your Apache gubbins. Head on over to…

cd /etc/apache2/sites-available

If you only have one domain on your server, you can just edit default.ssl.conf. I prefer to have separate conf files for each domain.

Make sure you update the /path/to/yourdomain.com part—you probably want a directory somewhere in /var/www or wherever your website’s files are sitting.

To exit the infernal text editor, hit ctrl and o, press enter in response to the prompt, and then hit ctrl and x.

If the yourdomain.com.conf didn’t previously exist, you’ll need to enable the configuration by running:

a2ensite yourdomain.com

Time to restart Apache. Fingers crossed…

service apache2 restart

If that worked, you should be able to go to https://yourdomain.com and see a lovely shiny padlock in the address bar.

Assuming that worked, everything is awesome! …for 90 days. After that, your certificates will expire and you’ll be left with a broken website.

Not to worry. You can update your certificates at any time. Test for yourself by doing a dry run:

/etc/certbot-auto renew --dry-run

You should see a message saying:

Processing /etc/letsencrypt/renewal/yourdomain.com.conf

And then, after a while:

** DRY RUN: simulating 'certbot renew' close to cert expiry
** (The test certificates below have not been saved.)
Congratulations, all renewals succeeded.

You could set yourself a calendar reminder to do the renewal (without the --dry-run bit) every few months. Or you could tell your server’s computer to do it by using a cron job. It’s not nearly as rude as it sounds.

You can fire up and edit your list of cron tasks with this command:

crontab -e

This tells the machine to run the renewal task at quarter past six every evening and log any results:

You know, I probably should have said this at the start of this post, but I should clarify that any advice I’ve given here should be taken with a huge pinch of salt—I have little to no idea what I’m doing. I’m not responsible for any flame-bursting-into that may occur. It’s probably a good idea to back everything up before even starting to do this.